Method and apparatus for forming rubber articles



V. H. BODLE April 1936.

METHOD AND APPARATUS FOR FORMING RUBBER ARTICLES Filed Jan. 24, 1954 En H155 d/E v Patented Apr. 14, 1936 UNTTED STATES METHOD AND APPARATUS FOR FORMING RUBBER ARTICLES Virgil H. Bodle, Newton,

Rubber Company, Inc

corporation of Delaware Mass., assignor to Hood Watertown, Mass., a

Application January 24, 1934, Serial No. 708,105 2 claims. (ci. ifs-41) This invention relates to the manufacture of formed rubber articles, especially such articles as footwear.

Rubber footwear hasY for a long time been formed upon a foot-shaped last by building sheet rubber parts onto such last to assemble and form the article, and more recently such articles have .been made by a procedure which has comprised molding a layer of rubber against a foot-:shaped form to provide a foot-shaped layer whichv has been turned inside out and finally shaped and vulcanized upon another foot-shaped last. In the last mentioned procedure the foot-shaped forms upon which the rubber has been deposited have in some instances been prepared by a procedure involving the building upon a foot-shaped support of a matrix surface of leather or sheet rubber reproductions of leather or other desired'surface, such sheet material having been carefully cut and sewn to fit the complex curves of the foot-shaped support, a procedure requiring considerable skillful effort. Also, the foot-shaped forms could be grouped only with considerable Waste space between them, requiring co'nsiderable space for the handling of them on a manufacturing scale and bulky tanks for dipping ygroups of the forms in the liquid dispersed rubber.

The Ichief objects of this invention are to provide for greater convenience and economy in the preparation and handling of the forms, to provide for the simultaneous dipping of a larger number of forms in a bath of a given size, and to provide at the same time for producing neatly and accurately shaped nal articles.

These and further objects Will be apparent from the following description, reference being had to the accompanying drawing in which:

Fig. l is a vertical section of a dipping tank having suspended therein a male-positive form constructed and utilized in accordance with the invention in its preferred form.

Fig. 2 is a section taken along the line 2-2 of Fig. 1.

Fig. 3 is an enlarged view of a portion of Fig. 2.

Fig. 4 is a view similar to Fig. 1 but showing a male-negative form produced from the positive form of Fig. l.

Fig. 5 is an enlarged section taken along the line 5 5 of Fig. 4.

Fig. 6 is a perspective View of a foot-shaped last having shaped upon it a male-positive matrix layer produced from the negative form of Fig. 4.

According to the preferred form of the invention a rigid form support IIl of metal or any other suitable material is provided, this vsupport being of only approximate foot-shape, having at sides with rounded edges, fbeing relatively thin and having `a surface yarea .sufiicient to cover the desiredfoot shape, the outline and dimensions preferably being such that the peripheries of horizontal sections of it in the position of Fig. 1 will equal substantially Vthe ,peripheries of horizontal sections taken at correspondingV levels of a form of the desired foot-shape so that a co-v- 10 eringmolded upon the flat form can be subsequently shaped upon the foot-shaped form with a minimum of objectionable stretching to effect the shaping. At one end, preferably the heeiend, the form is provided with an extension I I to'facil- 15 itate handling and suspension of it.

Upon this support is mounted a matrix, preferably in the form of a sock-like structure comprising pieces I2, I3 and I4 of flexible sheet material such as leather or sheet rubber, desirably 20 though not necessarily vulcanized, having a desired positive design formed in its surface. The pieces I2, I3 and I4 may be secured to the support by adhesion butl preferably are sewn together at seams I5, II6 and II to fit the support snugly 25 in the manner of a sock. 'Ihe upper end of the sock structure may be closed by a rubber tape I8 adhesively binding the margin of the sock onto the support. If desired, a decorative bead element ZIJ may be secured in the seams I6 and I'I, 30 the surface configuration of which, along with the surface form of the sock, will be reproduced in the nal article.

From the male-positive form of Figs. 1 to 3 the male-negative form of Figs. 4 and 5 is produced. 35 This is effected by molding upon the form of Fig. 1 a layer of rubber all around it, preferably by dipping the positive form. in a tank 2| of liquid dispersed rubber to deposit the rubber upon it, desirably with the aid of a coagulant. Y The 40 deposited rubber layer thus produced is then opened at its upper, larger end and is stripped from the form and mounted inside out upon a second support 22, identical with support I0, to provide a male-negative matrix 23. The rubber 45 of this matrix is preferably of a hard rubber compound so that by vulcanizing it upon the support 22, the form may be made rigid throughout. The upper end of the rubber matrix may be closed and bound to the support by means of a tape 24 applied before or after the vulcanization. The surface of this form being negative, the portion corresponding to the seam-bead 20 of the positive form will appear as a groove 25.

A layer of rubber is then deposited upon the matrix 23, as by dipping the form in a tank 26 of liquid dispersed rubber to provide a layer having molded in its surface a positive reproduction of the design, which layer, when stripped from the matrix and turned inside out, constitutes a malepositive reproduction 2l (Fig. 5) of the sock of Fig. 1. The male-positive layer is suitably trimmed at its ends, slit at the front, vand is shaped upon a foot-shaped last 28 to provide a shoe upper. The various other shoe components, such as the insole and outsole and lining are assembled with it upon the last in any desired manner and the whole then vulcanized upon the last, whereupon all parts will have the desired final shape.

In some cases, if desired, the sock structure of the rst flat form may surfaced sheet material, and the final positive article produced directly from this matrix. The

`preferred procedure described above is"better suited to large scale manufacture, however, as a greater number of high quality reproductions of the original designed surface is made possible, by the use of the intermediate, male-negative form. This and other variations may be made without departing from the scope of the invention as it is hereinafter claimed.

I claim:

1. The method of making the foot covering portion of an article of rubber footwear which comprises depositing rubber from a liquid dispersion be built up of negative of rubber upon a form and thereby producing a hollow rubber blank having an intricate surface design on its inner face and of a shape radically different in relative dimensions from that of the nal article and relatively narrow throughout as viewed from any. point in an extension of its medial plane but of a total area approximately equal to its area in the nished article, removing the blank from the form and turning it inside out so that the surface design is then on its exterior, then giving the blank its final shape as a part of the finished article and vulcanizing it in such shape, the original and iinal areas of the blank being so nearly equal that the surface design is not substantially distorted in changing the blank from its original to its final shape.

2. A dipping form for producing a rubber blank for the foot-covering portion of an article of rubber footwear, said form being, as viewed from any point in an extension of its substantially narrower throughout its extent than the corresponding part of the iinished article of footwear andosuchgirth at all positions along its length that its total area is approximately the same as that of the corresponding part of the nished article of footwear, said form having a surface design thereon and its shape being such that a rubber blank formed thereon can be reshaped to its nal form in the nished article of footwear without of the blank.

VIRGIL H. BODLE.

medial plane,

harmful stretching of any part 

